Atmospheric Testing of Nuclear Weapons
Atmospheric nuclear tests, conducted above ground, release vast amounts of radioactive particles into the atmosphere. These particles travel across the globe, causing widespread environmental contamination and health hazards. 528 atmospheric tests were conducted across sites around the world. These began just a few weeks before the bombings of Hiroshima and Nagasaki with the first test at Trinity, New Mexico. The atmospheric tests alone had a destructive force equal to 29,000 Hiroshima bombs. They dispersed radioactive particles far and wide, poisoning the soil, air, and water. These detonations permanently scarred the land, leaving many areas irradiated to this day. The radiation from these detonations worked its way into the ecosystems, leading to higher rates of cancer and illness among nearby populations who were often unwarned.

Consequences
Humanitarian Impacts
The over 500 atmospherics tests conducted had devastating and under-acknowledged humanitarian consequences.
Immediate Environmental Impact
The detonation of nuclear devices in the atmosphere causes immediate and severe environmental disruption:
Long-term Effects
The long-lasting presence of radioactive particles from atmospheric nuclear tests poses significant long-term risks.
Climate Implications
The environmental effects of atmospheric nuclear tests extend to broader climate issues
Case Study:
The Largest US Atmospheric Nuclear Test and Its Devastating Impact

Castle Bravo: the largest U.S. atmospheric nuclear detonation
Castle Bravo was the first and most powerful test of the Castle series conducted by the United States at Bikini Atoll in the Marshall Islands. Detonated on March 1, 1954, it remains one of the most significant and controversial atmospheric nuclear tests due to its unexpected yield and severe environmental and health impacts.
Castle Bravo highlighted the dangers of atmospheric nuclear testing and contributed to the growing international movement towards nuclear test bans. It played a role in the establishment of the Partial Test Ban Treaty of 1963, which prohibited atmospheric, outer space, and underwater nuclear tests.
Key points of Castle Bravo
- The explosion created a fireball that vaporized everything within a mile of the blast and generated a mushroom cloud reaching 130,000 feet into the atmosphere.
- The cloud of radioactive fallout contaminated a vast area of over 7,000 square miles downwind of the test site.
- Radioactive fallout settled over Bikini Atoll and neighboring atolls, contaminating the land and surrounding ocean. This rendered the area uninhabitable and disrupted marine ecosystems.
- The fallout reached inhabited atolls, including Rongelap and Utirik, exposing residents to high levels of radiation. This exposure led to acute radiation sickness, increased cancer rates, and long-term health issues.
- A Japanese fishing ship, the “Lucky Dragon” was also caught unawares in the fallout, resulting in severe radiation sickness among the crew.
- Military and civilian personnel involved in the test were also exposed to dangerous levels of radiation, resulting in various health problems over time.
- Residents of the neighboring atolls were evacuated 3 days after the detonation. Many were displaced for decades if not permanently. Efforts to decontaminate and rehabilitate the land have been ongoing, but significant areas remain unsafe for habitation.